Heart Care

'Silent,' Irregular Heartbeat Raises Stroke Risk

Even when a person has no obvious symptoms of atrial fibrillation (AF) - palpitations or a racing heart - AF may still make a stroke more likely. This is especially true if the person has other stroke risk factors, such as high blood pressure.

That's the conclusion of a study by researchers at McMaster University in Ontario, Canada. They looked at 2,580 people who had an implanted pacemaker but no history of AF. All were at least 65 years old and had a history of high blood pressure.

The researchers found that more than a third of the study participants had an episode of AF that lasted for more than six minutes. But of that number, 85 percent didn't notice the episode because they had no AF symptoms.

Stroke More Likely

Participants who had one silent AF episode within the first three months of the study were twice as likely to have a stroke, compared with their counterparts who did not experience any AF.

"Even though they are silent, these episodes are clearly associated with risk of stroke," says study author Jeff Healey, M.D.

The risk increased with each additional risk for stroke such as high blood pressure and diabetes, Dr. Healey says.

Talk with your doctor

The study results, published in the New England Journal of Medicine, don't mean that everyone should be tested for AF, but they should encourage people to know their risk factors for stroke and discuss them with their health care provider.

"We know that high blood pressure is a very important risk factor for stroke, and this study reinforces the importance of good primary care to pick up these risk factors," Dr. Healey says. "Further research will tell us if it makes sense to screen for silent AF in certain high-risk populations."

Always talk with your health care provider to find out more information.

Online Resources

(Our Organization is not responsible for the content of Internet sites.)

March 2012

What Is an Arrhythmia?

Arrhythmias are abnormal rhythms of the heart that cause the heart to pump less effectively.

Normally, an electrical impulse moves through the heart, causing the heart to contract 60 to 100 times a minute. Each contraction represents one heartbeat. The atria contract a fraction of a second before the ventricles so their blood empties into the ventricles before the ventricles contract.

Under some conditions, almost all heart tissue is capable of starting a heartbeat, or becoming the pacemaker. An arrhythmia occurs when:

The heart's natural pacemaker develops an abnormal rate or rhythm.

The normal conduction pathway is interrupted.

Another part of the heart takes over as pacemaker.

Always talk with your health care provider to find out more information.